import math
#1st line
pos_x1, pos_y1, pos_x2, pos_y2 = map(float,input().split(" "))

dist = math.sqrt((pos_x1-pos_x2)**2 + (pos_y1 - pos_y2)**2)
print(str(dist)) import math math pos_x1, pos_y1, pos_x2, pos_y2 = map(float,input().split(" ")) pos_x1 map(float,input().split(" ")) map float input().split(" ") ().split () input split " " pos_y1 pos_x2 pos_y2 dist = math.sqrt((pos_x1-pos_x2)**2 + (pos_y1 - pos_y2)**2) dist math.sqrt((pos_x1-pos_x2)**2 + (pos_y1 - pos_y2)**2) math.sqrt math sqrt (pos_x1-pos_x2)**2 + (pos_y1 - pos_y2)**2 (pos_x1-pos_x2)**2 pos_x1-pos_x2 pos_x1 pos_x2 2 (pos_y1 - pos_y2)**2 pos_y1 - pos_y2 pos_y1 pos_y2 2 print(str(dist)) print str(dist) str dist pos_x2, pos_y2 = map(float,input().split(" ")) map(float,input().split(" ")) pos_x2 dist = math.sqrt((pos_x1-pos_x2)**2 + (pos_y1 - pos_y2)**2) math.sqrt((pos_x1-pos_x2)**2 + (pos_y1 - pos_y2)**2) dist pos_y2 = map(float,input().split(" ")) map(float,input().split(" ")) pos_y2 pos_x1, pos_y1, pos_x2, pos_y2 = map(float,input().split(" ")) map(float,input().split(" ")) pos_x1 pos_y1, pos_x2, pos_y2 = map(float,input().split(" ")) map(float,input().split(" ")) pos_y1
import math
#1st line
pos_x1, pos_y1, pos_x2, pos_y2 = map(float,input().split(" "))

dist = math.sqrt((pos_x1-pos_x2)**2 + (pos_y1 - pos_y2)**2)
print(str(dist))